ii THE CHURCH OF S. JOHN OF THE STUDION 53 than the roofing of the aisles. It doubtless resembled the basilican churches at Salonica, either with clearstory windows, as in S. Demetrius^ or without such windows^ as in Eski Juma JamissL The nave terminates in a large apse, semicircular within and showing three sides on the exterior. Only the lower part is original; the Turkish superstructure is lower and on a smaller scale than the Byzantine portion it has replaced. There are no side chapels. Under the bema the Russian explorers discovered a small cruciform crypt. The large quantity of mosaic cubes found in the church during the recent Russian excavations proves that the church was decorated with mosaics, while the remains of iron plugs in the western wall for holding marble slabs show that the building had the customary marble revetment. But what is curious is to find the mortar pressed over the face of the stones3 and broad decorative joints formed by ruled incised lines and colour. Mr. W. S. George suggests that this was a temporary decoration executed pending some delay in the covering of the walls with marble. He also thinks that the importance given to the joint in late Byzantine work and in Turkish work may be a development from such early treatment of mortar. The floor of the church was paved with pieces of marble arranged in beautiful patterns5 in which figures of animals and scenes from classic mythology were inlaid. Gerlach1 noticed the beauty of the pavement, and Salzenberg2 represents a portion of it in his work on S. Sophia. But the members of the Russian Institute of Constantinople have had the good fortune to bring the whole pavement to light. A noticeable feature is the number of doors to the church, as in S, Irene, Besides the five doors already mentioned, leading into the interior from the narthex, there is a door at the eastern end of each aisle5 and close to each of these doors 5s found both in the southern and northern walls of the building an additional door surmounted by a 1 Sue passage from his Tagebttch quoted on page 50* 2 Altchristliehe Bewdwkmftter von Komtantinofelt Blatt iv.